1. Field
The present invention relates generally to turbochargers. More specifically, embodiments of the present invention concern a variable geometry turbocharger with adjustable vanes.
2. Discussion of Prior Art
Turbochargers are commonly used to improve the performance of reciprocating internal combustion engines. Prior art turbochargers include a turbine, which is powered by energy available from engine exhaust, and a compressor driven by the turbine to provide a compressed charge of intake air to the engine. It is well known for turbochargers to have operating, characteristics matched with a corresponding engine so that efficient turbocharger operation occurs over a range of engine load or engine speed. For instance, the turbine or compressor of the turbocharger can be sized for a particular engine. Also, turbochargers often employ a wastegate to vent exhaust air or intake air. Furthermore, it is known for a turbocharger to have features with variable geometry so that the turbocharger operating characteristic is adjustable.
While the prior art features permit turbocharger matching, prior art turbochargers suffer from various limitations. For instance, prior art variable geometry turbochargers are generally unreliable and prone to mechanical failure. Furthermore, prior art turbochargers include compressors that have a narrow operating range between surge and choke conditions, particularly under off-design operating conditions. The prior art turbochargers also fail to operate at peak efficiency over a range of engine load or engine speed.